Differential transformer type magnetic sensor and image forming apparatus

A differential transformer type magnetic sensor includes a drive coil, a reference coil, and a detection coil. These coils are formed by repeating a linear pattern that is formed on the first surface, penetrates the board, is formed on the second surface, penetrates the board, and returns to the first surface. The reference coil is disposed at a side of one end of the drive coil, and the detection coil is disposed at a side of the other end of the drive coil. Induced current flows to each of the reference coil and the detection coil due to magnetic flux generated as drive current flows to the drive coil. The reference coil and the detection coil are electrically connected so that a direction of the induced current flowing along the reference coil and a direction of the induced current flowing along the detection coil are opposite to each other.